.\"	$OpenBSD: strspn.3,v 1.10 2011/07/25 00:38:53 schwarze Exp $
.\"
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.\" This code is derived from software contributed to Berkeley by
.\" Chris Torek and the American National Standards Committee X3,
.\" on Information Processing Systems.
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.Dd $Mdocdate: July 25 2011 $
.Dt STRSPN 3
.Os
.Sh NAME
.Nm strspn
.Nd span a string
.Sh SYNOPSIS
.Fd #include <string.h>
.Ft size_t
.Fn strspn "const char *s" "const char *charset"
.Sh DESCRIPTION
The
.Fn strspn
function spans the initial part of the NUL-terminated string
.Fa s
as long as the characters from
.Fa s
occur in string
.Fa charset .
.Sh RETURN VALUES
The
.Fn strspn
function returns the number of characters spanned.
.Sh EXAMPLES
The following call to
.Fn strspn
will return 3, since the first three characters of string
.Fa s
are part of string
.Fa charset :
.Bd -literal -offset indent
char *s = "foobar";
char *charset = "of";
size_t span;

span = strspn(s, charset);
.Ed
.Sh SEE ALSO
.Xr memchr 3 ,
.Xr strchr 3 ,
.Xr strcspn 3 ,
.Xr strpbrk 3 ,
.Xr strrchr 3 ,
.Xr strsep 3 ,
.Xr strstr 3 ,
.Xr strtok 3 ,
.Xr wcsspn 3
.Sh STANDARDS
The
.Fn strspn
function conforms to
.St -ansiC .
.Sh HISTORY
The
.Fn strspn
function first appeared in
.At III
and was reimplemented for
.Bx 4.3 Tahoe .
